The present invention relates to a motor-driven compressor that includes a compression unit, an electric motor, and a motor driving circuit, which are arranged in this order along the axial direction of a rotation shaft.
Japanese Laid-Open Patent Publication No. 2005-201108 discloses a motor-driven compressor. The motor-driven compressor includes a housing accommodating an electric motor and a scroll compression unit. The electric motor drives the compression unit that compresses a fluid (refrigerant). The housing includes a first fluid passage located between the outer surface of the electric motor and the inner surface of the housing. The housing also includes a partition that separates the electric motor from the fluid and guides the fluid to the first fluid passage. The partition guides the fluid drawn into the housing near the electric motor to the first fluid passage. The fluid flowing in the first fluid passage absorbs heat from the electric motor.
In the motor-driven compressor, the compression unit, electric motor, and motor driving circuit are arranged along the axial direction of the rotation shaft. This increases the overall axial size of the motor-driven compressor. The axial size can be reduced by reducing the size of the electric motor, for example. However, to maintain the performance of the electric motor while reducing the size, a large amount of current needs to be applied to coils that are wound around teeth of a stator core that the electric motor includes. This increases the heat generated by the coils. Each coil includes an end located near the compression unit. Thus, the compression unit may heat the ends of the coils to a high temperature.